A very topical article on the Guardian Healthcare Network (read in full here) . . .
I completely relate to the anguish of waiting for post, and email would make it far quicker! As for the security of the Royal Mail, several significant medical letters of mine never arrived, despite being delivered to others cc'ed in!
One solution that might bypass the security fear around email would be to use something like HealthSpace, an online service already established by the NHS (see here) - being online it avoids the time and money costs of post, and already boasts a "Calendar" service, for patients to log all their appointments. Can that be shared with health professionals? The service already has "internationally recognised security measures" - does that overcome the issues of snail mail and email?